Hint: Video Game in Johnson House
When you enter the Johnson house there is a TV to your right with a game console on the floor in front of it, if you approach it, it will give the option to play a "Starship" game.

Cheat: Vehicle of Death
Whatever vehicle the player is using becomes invulnerable and gains the old tank ability to instantly destroy anything it touches. This applies to everything from the cars to motorcycles, golf carts, and even BMX bikes. Press L1, L2, L2, Up, Down, Down, Up, R1, R2, R2 during gameplay.

Cheat: Super-Punch
During gameplay, press UP, LEFT, X, TRIANGLE, R1, CIRCLE, CIRCLE, CIRCLE, L2. A message will confirm code entry. This will allow you to launch people when you punch them and finish them with a one hit kill.

Cheat: Recruit Pedestrians to Gang
Press DOWN, SQUARE, UP, R2, R2, UP, RIGHT, RIGHT, UP. A message will confirm code entry. You should be able to take anyone into your gang like pedestrians and rival gangs.

Cheat: Sandstorm
To make a sandstorm enter UP,DOWN,L1,L1,L2,L2,L1,L2,R1,R2